Regulation of VEGFR-3 expression and lymphangiogenesis in normal and inflamed tissues
Elevation of VEGFR-3, the primary mediator of lymphangiogenesis (i.e., new lymphatic vessel formation), is frequently associated with inflammation related to chronic disease and cancer. In the latter case, VEGFR-3 dependent lymphangiogenesis induced by inflamed tumors increases the incidence of dist...
Main Author: | |
---|---|
Format: | Others |
Published: |
OpenSIUC
2010
|
Subjects: | |
Online Access: | https://opensiuc.lib.siu.edu/dissertations/177 https://opensiuc.lib.siu.edu/cgi/viewcontent.cgi?article=1177&context=dissertations |
id |
ndltd-siu.edu-oai-opensiuc.lib.siu.edu-dissertations-1177 |
---|---|
record_format |
oai_dc |
spelling |
ndltd-siu.edu-oai-opensiuc.lib.siu.edu-dissertations-11772018-12-20T04:28:03Z Regulation of VEGFR-3 expression and lymphangiogenesis in normal and inflamed tissues Flister, Michael John Elevation of VEGFR-3, the primary mediator of lymphangiogenesis (i.e., new lymphatic vessel formation), is frequently associated with inflammation related to chronic disease and cancer. In the latter case, VEGFR-3 dependent lymphangiogenesis induced by inflamed tumors increases the incidence of distant metastasis, leading to decreased patient survival. However, the molecular mechanisms underlying inflammation-induced VEGFR-3 elevation and lymphangiogenesis are currently unknown. Two potential candidate genes that may regulate expression of VEGFR-3 are Prox1, the primary mediator of embryonic lymphangiogenesis, and NF-κB, the key intracellular regulator of inflammation-induced transcription. We hypothesized that the key inflammatory mediator, NF-κB, regulates transcription of key mediators of lymphangiogenesis, VEGFR-3 and Prox1. We further hypothesized that inflammation-induced elevation of VEGFR-3 and Prox1 are essential steps required for robust lymphangiogenesis in response to inflammation. The three primary goals of this study were to (1) delineate the time-course of events leading to inflammation-induced lymphangiogenesis in vivo; (2) clone and characterize the VEGFR-3 promoter and identify factors regulating VEGFR-3 expression in vitro; and (3) characterize the lymphatic phenotype of NF-κB p50 knockout mice. To begin testing these hypotheses, we used a mouse model of peritonitis to characterize induction of lymphangiogenesis and expression kinetics of NF-κB, Prox1 and VEGFR-3. In vivo time-course analysis of inflammation-induced lymphangiogenesis showed activation of NF-κB followed by sequential upregulation of Prox1 and VEGFR-3 that preceded lymphangiogenesis by 4 and 2 days, respectively. Characterization of the VEGFR-3 promoter by luciferase-reporter and ChIP assays showed direct activation by Prox1, NF-κB p50 and p65 transcription factors. This also revealed that Prox1 and NF-κB p50 bind in close proximity and synergistically activate the VEGFR-3 promoter. Characterization of p50 knockout mice revealed significantly decreased lymphatic vessel density in several organs that corresponded to reduced VEGFR-3 and Prox1 expression. Activation of NF-κB by inflammatory stimuli also elevated expression of NF-κB, Prox1 and VEGFR-3 in cultured lymphatic endothelial cells, which enhanced proliferation and migration in response to the VEGFR-3-specific ligand, VEGF-C152S. Collectively, our findings suggest that induction of the NF-κB pathway by inflammatory stimuli activates Prox1, and both NF-κB and Prox1 activate the VEGFR-3 promoter leading to increased receptor expression in lymphatic endothelial cells. This, in turn, enhances the responsiveness of pre-existing lymphatic endothelium to VEGFR-3 binding factors, VEGF-C and VEGF-D, ultimately resulting in robust lymphangiogenesis. 2010-12-01T08:00:00Z text application/pdf https://opensiuc.lib.siu.edu/dissertations/177 https://opensiuc.lib.siu.edu/cgi/viewcontent.cgi?article=1177&context=dissertations Dissertations OpenSIUC Inflammation Lymphangiogenesis Lymphatic NF-kappaB Prox1 VEGFR-3 |
collection |
NDLTD |
format |
Others
|
sources |
NDLTD |
topic |
Inflammation Lymphangiogenesis Lymphatic NF-kappaB Prox1 VEGFR-3 |
spellingShingle |
Inflammation Lymphangiogenesis Lymphatic NF-kappaB Prox1 VEGFR-3 Flister, Michael John Regulation of VEGFR-3 expression and lymphangiogenesis in normal and inflamed tissues |
description |
Elevation of VEGFR-3, the primary mediator of lymphangiogenesis (i.e., new lymphatic vessel formation), is frequently associated with inflammation related to chronic disease and cancer. In the latter case, VEGFR-3 dependent lymphangiogenesis induced by inflamed tumors increases the incidence of distant metastasis, leading to decreased patient survival. However, the molecular mechanisms underlying inflammation-induced VEGFR-3 elevation and lymphangiogenesis are currently unknown. Two potential candidate genes that may regulate expression of VEGFR-3 are Prox1, the primary mediator of embryonic lymphangiogenesis, and NF-κB, the key intracellular regulator of inflammation-induced transcription. We hypothesized that the key inflammatory mediator, NF-κB, regulates transcription of key mediators of lymphangiogenesis, VEGFR-3 and Prox1. We further hypothesized that inflammation-induced elevation of VEGFR-3 and Prox1 are essential steps required for robust lymphangiogenesis in response to inflammation. The three primary goals of this study were to (1) delineate the time-course of events leading to inflammation-induced lymphangiogenesis in vivo; (2) clone and characterize the VEGFR-3 promoter and identify factors regulating VEGFR-3 expression in vitro; and (3) characterize the lymphatic phenotype of NF-κB p50 knockout mice. To begin testing these hypotheses, we used a mouse model of peritonitis to characterize induction of lymphangiogenesis and expression kinetics of NF-κB, Prox1 and VEGFR-3. In vivo time-course analysis of inflammation-induced lymphangiogenesis showed activation of NF-κB followed by sequential upregulation of Prox1 and VEGFR-3 that preceded lymphangiogenesis by 4 and 2 days, respectively. Characterization of the VEGFR-3 promoter by luciferase-reporter and ChIP assays showed direct activation by Prox1, NF-κB p50 and p65 transcription factors. This also revealed that Prox1 and NF-κB p50 bind in close proximity and synergistically activate the VEGFR-3 promoter. Characterization of p50 knockout mice revealed significantly decreased lymphatic vessel density in several organs that corresponded to reduced VEGFR-3 and Prox1 expression. Activation of NF-κB by inflammatory stimuli also elevated expression of NF-κB, Prox1 and VEGFR-3 in cultured lymphatic endothelial cells, which enhanced proliferation and migration in response to the VEGFR-3-specific ligand, VEGF-C152S. Collectively, our findings suggest that induction of the NF-κB pathway by inflammatory stimuli activates Prox1, and both NF-κB and Prox1 activate the VEGFR-3 promoter leading to increased receptor expression in lymphatic endothelial cells. This, in turn, enhances the responsiveness of pre-existing lymphatic endothelium to VEGFR-3 binding factors, VEGF-C and VEGF-D, ultimately resulting in robust lymphangiogenesis. |
author |
Flister, Michael John |
author_facet |
Flister, Michael John |
author_sort |
Flister, Michael John |
title |
Regulation of VEGFR-3 expression and lymphangiogenesis in normal and inflamed tissues |
title_short |
Regulation of VEGFR-3 expression and lymphangiogenesis in normal and inflamed tissues |
title_full |
Regulation of VEGFR-3 expression and lymphangiogenesis in normal and inflamed tissues |
title_fullStr |
Regulation of VEGFR-3 expression and lymphangiogenesis in normal and inflamed tissues |
title_full_unstemmed |
Regulation of VEGFR-3 expression and lymphangiogenesis in normal and inflamed tissues |
title_sort |
regulation of vegfr-3 expression and lymphangiogenesis in normal and inflamed tissues |
publisher |
OpenSIUC |
publishDate |
2010 |
url |
https://opensiuc.lib.siu.edu/dissertations/177 https://opensiuc.lib.siu.edu/cgi/viewcontent.cgi?article=1177&context=dissertations |
work_keys_str_mv |
AT flistermichaeljohn regulationofvegfr3expressionandlymphangiogenesisinnormalandinflamedtissues |
_version_ |
1718802205881925632 |